Method and apparatus for encoding transport block

ABSTRACT

A method for encoding a transport block in a wireless communication system, and a wireless apparatus therefore are discussed. The method according to one embodiment includes determining a size of the transport block; attaching a first cyclic redundancy check (CRC) code to the transport block having the determined size to produce a first CRC-attached transport block; segmenting the first CRC-attached transport block into a plurality of code blocks when a size of the first CRC-attached transport block is larger than a maximum code block size; attaching a second CRC code to each of the plurality of code blocks to produce a plurality of second CRC-attached code blocks; and encoding the second CRC-attached code blocks by a turbo-encoder. The size of the transport block is determined from among a plurality of first predetermined transport block sizes and a plurality of second predetermined transport block sizes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of co-pending U.S. application Ser. No. 14/074,137 filed on Nov. 7, 2013, which claims the benefit of priority of U.S. Provisional Application No. 61/732,893 filed on Dec. 3, 2012. All these applications are incorporated by reference in their entirety herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to wireless communications, and more particularly, to a method and apparatus for encoding a transport block.

2. Related Art

Extensive researches are underway in LTE (long term evolution) release 12 to improve performance in terms of capacity, coverage, coordination between cells, and costs. There is an ongoing discussion to introduce various techniques in the LTE release 12 in a technical aspect to improve performance, such as small cell enhancement, macro cell enhancement, new carrier type, machine type communication, etc.

The LTE release 12 aims at improving the capacity and coverage, which may be achieved by using small cell enhancement based on inter-site carrier aggregation, LTE-WLAN (wireless local area network) integration, and micro cell enhancement. Assuming a case where a cell is decreased in size, inter-cell movement of a terminal occurs frequently, which may result in an increase in an amount of traffic signaled when the terminal moves. To solve such a problem, a method of optimizing a small cell by decreasing signaling transmitted from an RAN (radio access network) to a core network on the basis of the small cell enhancement is under discussion in the LTE release 12.

In addition, an NCT (new carrier type) discussed in the LTE release 12 is a frame type which is newly defined differently from a legacy frame structure. Although the NCT can be a carrier type optimized for a small cell, it can also be applied to a macro cell. For example, in the NCT, an overhead generated by transmitting a reference signal such as a CRS (cell-specific reference signal) can be decreased, and a downlink control channel can be demodulated on the basis of a DM-RS (demodulation reference signal). By newly defining the NCT, energy of a base station can be saved, and an interference generated in a HetNet (heterogeneous network) can be decreased. In addition, the use of the NCT can decrease a reference signal overhead generated in data transmission using a plurality of downlink antennas. More specifically, although the legacy frame structure (e.g., a CP (cyclic prefix) length, a subframe structure, a duplexing mode, etc.) is maintained in the NCT, a control channel and/or a reference signal can be newly defined.

SUMMARY OF THE INVENTION

The present invention provides a method of encoding a transport block.

The present invention also provides an apparatus for encoding a transport block.

According to one aspect of the present invention, a method for encoding a transport block in a wireless communication system is provided. The method includes: determining, by a transmitter, a size of transport block; dividing, by the transmitter, the transport block into at least one code block based on the size of transport block; interleaving, by the transmitter, the at least one code block by an interleaver; and performing, by the transmitter, a turbo coding for the interleaved at least one code block, wherein the size of transport block is determined based on the number of the divided code blocks.

According to another aspect of the present invention, a wireless apparatus configured for encoding a transport block in a wireless communication system is provided. The wireless apparatus includes: a transceiver configured to receive radio signals; and a processor operatively coupled with the transceiver and configured to: determine a size of transport block; divide the transport block into at least one code block based on the size of transport block; interleave the at least one code block by an interleaver; and perform a turbo coding for the interleaved at least one code block, wherein the size of transport block is determined based on a number of the divided code blocks.

Data transmission and reception performance can be improved by decreasing the number of dummy bits when coding a transport block.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a radio frame structure in LTE (long term evolution).

FIG. 2 shows an example of a resource grid for one downlink slot.

FIG. 3 shows a structure of a downlink subframe.

FIG. 4 shows a structure of an uplink subframe.

FIG. 5 is a block diagram showing a method of generating PDCCH (physical downlink control channel) data.

FIG. 6 shows an example of monitoring a PDCCH.

FIG. 7 shows a downlink subframe to which a reference signal and a control channel are allocated in 3GPP (3rd generation partnership project) LTE.

FIG. 8 is an example of a subframe having an EPDCCH (enhanced PDCCH).

FIG. 9 shows the concept of a method of processing a downlink transport channel according to an embodiment of the present invention.

FIG. 10 shows the concept of a method of performing code block segmentation.

FIG. 11 shows the concept of a method of performing rate matching.

FIG. 12 shows the concept of a resource block pair according to an embodiment of the present invention.

FIG. 13 is a flowchart showing a method of performing turbo coding for a transport block according to an embodiment of the present invention.

FIG. 14 is a block diagram of a wireless communication system according to an embodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A wireless device may be fixed or mobile, and may be referred to as another terminology, such as a UE (user equipment), an MS (mobile station), an MT (mobile terminal), a UT (user terminal), an SS (subscriber station), a PDA (personal digital assistant), a wireless modem, a handheld device, a terminal, a wireless terminal, etc. The wireless device may also be a device supporting only data communication such as an MTC (machine-type communication) device.

A BS (base station) is generally a fixed station that communicates with the wireless device, and may be referred to as another terminology, such as an eNB (evolved-NodeB), a BTS (base transceiver system), an access point, etc.

Operations of a UE and/or a BS in 3GPP (3rd generation partnership project) LTE (long term evolution) or 3GPP LTE-A defined based on each of releases of 3GPP TS (technical specification) will be described hereinafter. In addition, the present invention may also apply to various wireless communication networks other than the 3GPP LTE/3GPP LTE-A. In the following description, LTE and/or LTE-A are collectively referred to as LTE.

FIG. 1 shows a radio frame structure in LTE.

In 3GPP LTE, a structure of a radio frame 100 is disclosed in the section 5 of 3GPP TS 36.211 V8.2.0 (2008-03) “Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation (Release 8)”.

Referring to FIG. 1, the radio frame 100 consists of 10 subframes 120. One subframe 120 consists of two slots 140. The radio frame 100 may be indexed based on the slots 140 indexed from a slot #0 to a slot #19, or may be indexed based on the subframes 120 indexed from a subframe #0 to a subframe #9. For example, the subframe #0 may include the slot #0 and the slot #1.

A time required to transmit one subframe 120 is defined as a TTI (transmission time interval). The TTI may be a scheduling unit for data transmission. For example, a length of one radio frame 100 may be 1 millisecond (ms), a length of one subframe 120 may be 1 ms, and a length of one slot 140 may be 0.5 ms.

One slot 140 includes a plurality of OFDM (orthogonal frequency division multiplexing) symbols in a time domain, and includes a plurality of subcarriers in a frequency domain. In LTE, a BS uses OFDMA as an access scheme in a downlink channel. The OFDM symbol is for representing one symbol period, and may be referred to as other terms according to a multiple access scheme. For example, an SC-FDMA (single carrier-frequency division multiple access) may be used as the multiple access scheme in an uplink channel in which data is transmitted from a UE to a BS. A symbol duration in which data is transmitted through the uplink channel may be called an SC-FDMA symbol.

The structure of the radio frame 100 described in FIG. 1 is one embodiment for a frame structure. Therefore, the number of subframes 120 included in the radio frame 100, the number of slots 140 included in the subframe 120, or the number of OFDM symbols included in the slot 140 may be changed variously to define a new radio frame format.

In the structure of the radio frame, the number of symbols included in one slot may vary depending on which CP (cyclic prefix) is used. For example, if the radio frame uses a normal CP, one slot may include 7 OFDM symbols. If the radio frame uses an extended CP, one slot may include 6 OFDM symbols.

As a duplexing scheme, a wireless communication system may use an FDD (frequency division duplex) scheme, a TDD (time division duplex) scheme, etc. In the FDD scheme, uplink transmission and downlink transmission may be performed based on different frequency bands. In the TDD scheme, uplink transmission and downlink transmission may be performed by using a time-based division scheme based on the same frequency band. Channel responses of the TDD scheme may have a reciprocal property since the same frequency band is used. That is, in the TDD scheme, a downlink channel response and an uplink channel response may be almost identical in a given frequency domain. Therefore, a TDD-based wireless communication system may acquire channel state information of a downlink channel from channel state information of an uplink channel. In the TDD system, a full frequency band is time-divided into uplink transmission and downlink transmission, and thus downlink transmission performed by the BS and uplink transmission performed by the UE may be performed simultaneously.

FIG. 2 shows an example of a resource grid for one downlink slot.

The downlink slot includes a plurality of OFDM symbols in a time domain, and includes NRB resource blocks in a frequency domain. The number NRB of resource blocks included in the downlink slot may be determined according to a downlink transmission bandwidth configured in a cell. For example, in the LTE system, NRB may be any one value in the range of 60 to 110 according to a transmission bandwidth in use. One resource block 200 may include a plurality of subcarriers in the frequency band. A structure of an uplink slot may be the same as the aforementioned structure of the downlink slot.

Each element on the resource grid is referred to as a resource element 220. The resource element 220 on the resource grid may be identified by an index pair (k,l). Herein, k(k=0, . . . , NRB×12−1) denotes a subcarrier index in the frequency domain, and l(l=0, . . . , 6) denotes an OFDM symbol index in the time domain.

Herein, one resource block 200 may include 7×12 resource elements 220 consisting of 7 OFDM symbols in the time domain and 12 subcarriers in the frequency domain. Such a size is one example, and thus the number of OFDM symbols and the number of subcarriers constituting one resource block 200 may change. A resource block pair indicates a resource unit including two resource blocks.

The number of OFDM symbols included in one slot may have a different value depending on a CP as described above. In addition, the number of resource blocks included in one slot may vary depending on a size of a full frequency bandwidth.

FIG. 3 shows a structure of a downlink subframe.

A downlink subframe 300 may be divided into two slots 310 and 320 according to a time. Each of the slots 310 and 320 includes 7 OFDM symbols in a normal CP case. A resource region corresponding to first three OFDM symbols (i.e., in case of 1.4 MHz bandwidth, up to 4 OFDM symbols) included in the first slot 310 of the subframe 300 may be used as a control region 350 to which control channels are allocated. The remaining OFDM symbols may be used as a data region 360 to which a traffic channel such as a PDSCH (physical downlink shared channel) is allocated.

A PDCCH (physical downlink control channel) may be a control channel for transmitting a resource allocation and transmission format of a DL-SCH (downlink-shared channel), resource allocation information of a UL-SCH (uplink shared channel), paging information on a PCH, system information on a DL-SCH, a resource allocation of a higher layer control message such as a random access response transmitted through a PDSCH, a transmission power control command for individual UEs included in any UE group, activation of a VoIP (voice over internet protocol), etc. A plurality of units of transmitting PDCCH data may be defined within the control region 350. The UE may acquire control data by monitoring the plurality of units of transmitting the PDCCH data. For example, the PDCCH data may be transmitted to the UE on the basis of an aggregation of one or several consecutive CCEs (control channel elements). The CCE may be one unit of transmitting the PDCCH data. The CCE may include a plurality of resource element groups. The resource element group is a resource unit including four available resource elements.

A BS determines a PDCCH format according to DCI (downlink control information) to be transmitted to a UE, and attaches a CRC (cyclic redundancy check) to control information. The CRC is masked with a unique identifier (referred to as an RNTI (radio network temporary identifier)) according to an owner or usage of the PDCCH. If the PDCCH is for a specific UE, a unique identifier (e.g., C-RNTI (cell-RNTI)) of the UE may be masked to the CRC. Alternatively, if the PDCCH is for a paging message, a paging indicator identifier (e.g., P-RNTI (paging-RNTI)) may be masked to the CRC. If the PDCCH is for an SIB (system information block), a system information identifier and an SI-RNTI (system information-RNTI) may be masked to the CRC. To indicate a random access response that is a response for transmission of a random access preamble of the UE, an RA-RNTI (random access-RNTI) may be masked to the CRC.

FIG. 4 shows a structure of an uplink subframe.

The uplink subframe may be divided into control regions 430 and 440 and a data region 450. A PUCCH (physical uplink control channel) for carrying uplink control information is allocated to the control regions 430 and 440. A PUSCH (physical uplink shared channel) for carrying data is allocated to the data region 450. When indicated by a higher layer, a UE may support simultaneous transmission of the PUSCH and the PUCCH.

The PUCCH for one UE is allocated in an RB (resource block) pair in a subframe. RBs belonging to the RB pair occupy different subcarriers in each of a 1st slot 410 and a 2nd slot 420. A frequency occupied by the RBs belonging to the RB pair changes at a slot boundary. This is called that the RB pair allocated to the PUCCH is frequency-hopped at the slot boundary. Since the UE transmits the UCI on a time basis through different subcarriers, a frequency diversity gain can be obtained. m is a location index indicating a logical frequency-domain location of the RB pair allocated to the PUCCH in the subframe.

Examples of uplink control information transmitted on a PUCCH may include HARQ (hybrid automatic repeat request) ACK (acknowledgement)/NACK (non-acknowledgement), CQI (channel quality indicator) indicating a downlink channel state, SR (scheduling request) which is an uplink radio resource allocation request, etc.

The PUSCH is a channel mapped to a UL-SCH (uplink shared channel) which is a transport channel. Uplink data transmitted through the PUSCH may be a transport block which is a data block for the UL-SCH transmitted during a TTI. The transport block may include user information. In addition, the uplink data may be multiplexed data. The multiplexed data may be obtained by multiplexing control information and a transport block for the UL-SCH. Examples of the control information multiplexed to the data may include CQI, PMI (precoding matrix indicator), HARQ ACK/NACK, RI (rank indicator), etc. Alternatively, the uplink data may consist of only the control information.

FIG. 5 is a block diagram showing a method of generating PDCCH data.

In FIG. 5, a method of generating PDCCH data is described in detail.

A UE performs blind decoding to detect a PDCCH. The blind decoding may be performed on the basis of an identifier masked to a CRC (cyclic redundancy check) of a received PDCCH (referred to as a candidate PDCCH). By checking an CRC error of the received PDCCH data, the UE may determine whether the PDCCH data is its own control data.

A BS determines a PDCCH format according to DCI (downlink control information) to be transmitted to the UE and thereafter attaches a CRC to the DCI, and masks a unique identifier (referred to as an RNTI (radio network temporary identifier)) to the CRC according to an owner or usage of the PDCCH (block 510).

If the PDCCH is for a specific UE, the BS may mask a unique identifier (e.g., C-RNTI (cell-RNTI)) of the UE to the CRC. Alternatively, if the PDCCH is for a paging message, the BS may mask a paging indication identifier (e.g., P-RNTI (paging-RNTI)) to the CRC. If the PDCCH is for system information, the BS may mask a system information identifier (e.g., SI-RNTI (system information-RNTI)) to the CRC. In addition thereto, the BS may mask an RA-RNTI (random access-RNTI) to the CRC in order to indicate a random access response that is a response for transmission of a random access preamble of the UE, and may mask a TPC-RNTI to the CRC in order to indicate a TPC (transmit power control) command for a plurality of UEs.

A PDCCH masked with the C-RNTI may transmit control information for a specific UE (such information is called UE-specific control information), and a PDCCH masked with a different RNTI may transmit common control information received by all or a plurality of UEs in a cell. A plurality of DCI formats may be defined to transmit PDCCH data. This will be additionally described in detail.

The BS encodes the CRC-attached DCI to generate coded data (block 520). Encoding includes channel encoding and rate matching.

The BS generates modulation symbols by performing modulation on the coded data (block 530).

The BS maps the modulation symbols to physical REs (resource elements) (block 540). The BS may map the modulation symbols to the respective REs.

As described above, a control region in a subframe includes a plurality of CCEs (control channel elements). The CCE is a logical allocation unit used to provide the PDCCH with a coding rate depending on a radio channel state, and corresponds to a plurality of REGs (resource element groups). The REG includes a plurality of resource elements. One REG includes 4 REs. One CCE includes 9 REGs. The number of CCEs used to configure one PDCCH may be selected from a set {1, 2, 4, 8}. Each element of the set {1, 2, 4, 8} is referred to as a CCE aggregation level.

The BS may determine the number of CCEs used in transmission of the PDCCH according to a channel state. For example, if a downlink channel state is good, the BS may use one CCE to transmit PDCCH data to the UE. On the contrary, if the downlink channel state is not good, the BS may use 8 CCEs to transmit PDCCH data to the UE.

A control channel consisting of one or more CCEs may perform interleaving in an REG unit, and may be mapped to a physical resource after performing cyclic shift based on a cell ID (identifier).

FIG. 6 shows an example of monitoring a PDCCH. The section 9 of 3GPP TS 36.213 V10.2.0 (2011-06) may be incorporated herein by reference.

A UE may perform blind decoding to detect the PDCCH. The blind decoding is a scheme in which a specific identifier is de-masked from a CRC of received PDCCH (referred to as candidate PDCCH) data and thereafter whether the PDCCH is its own control channel is determined by performing CRC error checking. The UE cannot know about a specific position in a control region in which its PDCCH data is transmitted and about a specific CCE aggregation level or DCI format used in transmission.

A plurality of PDCCHs may be transmitted in one subframe. The UE monitors the plurality of PDCCHs in every subframe. Herein, monitoring is an operation in which the UE attempts to perform blind decoding on the PDCCH.

The 3GPP LTE uses a search space to reduce an overload caused when the UE performs the blind decoding. The search space may also be called a monitoring set of a CCE for PDCCH searching. The UE may monitor the PDCCH on the basis of the search space.

The search space is classified into a common search space and a UE-specific search space. The common search space is a space for searching for a PDCCH having common control information and consists of 16 CCEs indexed with 0 to 15. The common search space supports a PDCCH having a CCE aggregation level of {4, 8}. However, a PDCCH (e.g., DCI formats 0, 1A) for carrying UE-specific information may also be transmitted in the common search space. The UE-specific search space supports a PDCCH having a CCE aggregation level of {1, 2, 4, 8}.

Table 1 shows the number of PDCCH candidates monitored by the UE.

TABLE 1 Number of Search space S_(k) ^((L)) PDCCH Aggregation Size candidates DCI Type level L [in CCEs] M^((L)) format UE- 1 6 6 0, 1, 1A, 1B, specific 2 12 6 1D, 2, 2A 4 8 2 8 16 2 Common 4 16 4 0, 1A, 1C, 8 16 2 3/3A

A size of search space is determined by Table 1 above, and a start point of the search space is defined differently in the common search space and the UE-specific search space. Although a start point of the common search space is fixed irrespective of a subframe, a start point of the UE-specific search space may vary in every subframe according to a UE identifier (e.g., C-RNTI), a CCE aggregation level, and/or a slot number in a radio frame. If the start point of the UE-specific search space exists in the common search space, the UE-specific search space and the common search space may overlap.

A set of PDCCH candidates monitored by the UE may be defined according to the search space. In the aggregation level 1, 2, 4, or 8, a search space S_(k) ^((L)) is defined as the set of PDCCH candidates. In the search space S_(k) ^((L)), a CCE corresponding to a PDCCH candidate m is given by Equation 1 below. L·{(Y _(k) +m′)mod └N _(CCE,k) /L┘}+i  <Equation 1>

Herein, i=0, . . . , L−1. If the search space is a common search space, m′=m. If the search space is a UE-specific search space, m′=m+M^((L))·n_(CI) when a CIF (carrier indicator field) is set to the UE, where n_(CI) is a value of the set CIF. Further, m′=m when the CIF is not set to the UE. Herein, m=0, . . . , M^((L))−1 where M^((L)) is the number of PDCCH candidates for monitoring a given search space.

In a common search space, Y_(k) is set to 0 with respect to two aggregation levels L=4 and L=8. In a UE-specific search space of the aggregation level L, a variable Y_(k) is defined by Equation 2 below. Y _(k)=(A·Y _(k-1))mod D  <Equation 2>

Herein, Y⁻¹=n_(RNTI)≠0, A=39827, D=65537, k=└n_(s)/2┘. ns denotes a slot number in a radio frame.

When a wireless device monitors a PDCCH on the basis of a C-RNTI, a search space and a DCI format to be monitored are determined according to a transmission mode of a PDSCH. Table 2 below shows an example of PDCCH monitoring in which the C-RNTI is set.

TABLE 2 Transmission Transmission mode of mode DCI format search space PDSCH based on PDCCH Mode 1 DCI format 1A common and Single antenna port, port 0 UE specific DCI format 1 UE specific Single antenna port, port 0 Mode 2 DCI format 1A common and Transmit diversity UE specific DCI format 1 UE specific Transmit diversity Mode 3 DCI format 1A common and Transmit diversity UE specific DCI format 2A UE specific CDD (Cyclic Delay Diversity) or Transmit diversity Mode 4 DCI format 1A common and Transmit diversity UE specific DCI format 2 UE specific Closed-loop spatial multiplexing Mode 5 DCI format 1A common and Transmit diversity UE specific DCI format 1D UE specific MU-MIMO (Multi-user Multiple Input Multiple Output) Mode 6 DCI format 1A common and Transmit diversity UE specific DCI format 1B UE specific Closed-loop spatial multiplexing Mode 7 DCI format 1A common and If the number of PBCH UE specific transmission ports is 1, single antenna port, port 0, otherwise Transmit diversity DCI format 1 UE specific Single antenna port, port 5 Mode 8 DCI format 1A common and If the number of PBCH UE specific transmission ports is 1, single antenna port, port 0, otherwise, Transmit diversity DCI format 2B UE specific Dual layer transmission (port 7 or 8), or single antenna port, port 7 or 8

The usage of the DCI format is classified as shown in Table 3 below.

TABLE 3 DCI format Contents DCI format 0 It is used for PUSCH scheduling. DCI format 1 It is used for scheduling of one PDSCH codeword. DCI format 1A It is used for compact scheduling and random access process of one PDSCH codeword. DCI format 1B It is used in simple scheduling of one PDSCH codeword having precoding information. DCI format 1C It is used for very compact scheduling of one PDSCH codeword. DCI format 1D It is used for simple scheduling of one PDSCH codeword having precoding and power offset information. DCI format 2 It is used for PDSCH scheduling of UEs configured to a closed-loop spatial multiplexing mode. DCI format 2A It is used for PDSCH scheduling of UEs configured to an open-loop spatial multiplexing mode. DCI format 3 It is used for transmission of a TPC command of a PUCCH and a PUSCH having a 2-bit power adjustment. DCI format 3A It is used for transmission of a TPC command of a PUCCH and a PUSCH having a 1-bit power adjustment.

According to an RNTI masked to a CRC used when DCI is generated, a search space and a DCI format to be used may be set differently. Table 4 below shows a search space and a DCI format of a control channel used when SI-RNTI, P-RNTI, or RA-RNTI is masked to the CRC of the DCI.

TABLE 4 search Transmission mode of PDSCH DCI format space based on PDCCH DCI format common If the number of PBCH transmission 1C ports is 1, single antenna port, port 0, otherwise Transmit diversity DCI format common If the number of PBCH transmission 1A ports is 1, single antenna port, port 0, otherwise Transmit diversity

Table 5 below shows a DCI format and a search space of a control channel used when SPS-C-RNT is masked to the CRC of the DCI.

TABLE 5 Transmission Transmission mode of mode DCI format search space PDSCH based on PDCCH Mode 1 DCI format 1A common and Single antenna port, port 0 UE specific DCI format 1 UE specific Single antenna port, port 0 Mode 2 DCI format 1A common and Transmit diversity UE specific DCI format 1 UE specific Transmit diversity Mode 3 DCI format 1A common and Transmit diversity UE specific DCI format 2A UE specific Transmit diversity Mode 4 DCI format 1A common and Transmit diversity UE specific DCI format 2 UE specific Transmit diversity Mode 5 DCI format 1A common and Transmit diversity UE specific Mode 6 DCI format 1A common and Transmit diversity UE specific Mode 7 DCI format 1A common and Single antenna port, port 5 UE specific DCI format 1 UE specific Single antenna port, port 5 Mode 8 DCI format 1A common and Single antenna port, port 7 UE specific DCI format 2B UE specific Single antenna port, port 7 or 8 Mode 9 DCI format 1A common and Single antenna port, port 7 UE specific DCI format 2C UE specific Single antenna port, port 7 or 8  Mode 10 DCI format 1A common and Single antenna port, port 7 UE specific DCI format 2D UE specific Single antenna port, port 7 or 8

Table 6 below shows a DCI format and a search area of a control channel used when temporary C-RNTI is masked to the CRC of the DCI.

TABLE 6 Transmission mode of PDSCH DCI format search space based on PDCCH DCI format 1A common and If the number of PBCH transmission UE specific ports is 1, single antenna port, port 0, otherwise Transmit diversity DCI format 1 UE specific If the number of PBCH transmission ports is 1, single antenna port, port 0, otherwise Transmit diversity

FIG. 7 shows a downlink subframe to which a reference signal and a control channel are allocated in 3GPP LTE.

The downlink subframe may be divided into a control region and a data region. For example, in the downlink subframe, the control region (or a PDCCH region) includes first three OFDM symbols, and the data region in which a PDSCH is transmitted includes the remaining OFDM symbols.

A PCFICH, a PHICH, and/or a PDCCH are transmitted in the control region.

A PHICH (physical HARQ ACK/NACK indicator channel) may transmit HARQ (hybrid automatic retransmission request) information in response to uplink transmission.

A PCFICH (physical control format indicator channel) may transmit information regarding the number of OFDM symbols allocated to the PDCCH. For example, a control format indictor (CFI) of the PCFICH may indicate three OFDM symbols. A region excluding a resource in which the PCFICH and/or the PHICH are transmitted in the control region is a PDCCH region in which the UE monitors the PDCCH.

Various reference signals may be transmitted in the subframe.

A CRS (cell-specific reference signal) is a reference signal that can be received by all UEs in a cell, and may be transmitted across a full downlink frequency band. In FIG. 6, ‘R0’ indicates an RE used to transmit a CRS for a first antenna port, ‘R1’ indicates an RE used to transmit a CRS for a second antenna port, ‘R2’ indicates an RE used to transmit a CRS for a third antenna port, and ‘R3’ indicates an RE used to transmit a CRS for a fourth antenna port.

An RS sequence r_(l,n) _(s) (m) for a CRS is defined as follows.

$\begin{matrix} {{r_{l,{ns}}(m)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {2m} \right)}}} \right)} + {j\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {{2m} + 1} \right)}}} \right)}}} & \left\langle {{Equation}\mspace{14mu} 3} \right\rangle \end{matrix}$

Herein, m=0, 1, . . . , 2N_(RB) ^(max,DL)−1. N_(RB) ^(max,DL) is the maximum number of RBs. ns is a slot number in a radio frame. 1 is an OFDM symbol index in a slot.

A pseudo-random sequence is defined by a length-31 gold sequence as follows. c(n)=(x ₁(n+Nc)+x ₂(n+Nc))mod 2 x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod 2 x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod 2  <Equation 4>

Herein, Nc=1600, and a first m-sequence is initialized as x1(0)=1, x1(n)=0, m=1, 2, . . . , 30. A second m-sequence is initialized as c_(init)=2¹⁰·(7·(n_(s)+1)+l+1)·(2·N_(ID) ^(cell)+1)+2·N_(ID) ^(cell)+N_(CP) at a start of each OFDM symbol. N_(ID) ^(cell) is a physical cell identifier (PCI). N_(CP) is set to N_(CP)=1 in a normal CP case, and is set to N_(CP)=0 in an extended CP case.

In addition, a URS (UE-specific Reference Signal) may be transmitted in the subframe. Whereas the CRS is transmitted in a full region of the subframe, the URS is a reference signal transmitted in a data region of the subframe and is used to demodulate the PDSCH. In FIG. 7, ‘R5’ indicates an RE used to transmit the URS. A DM-RS is a reference signal used to demodulate EPDCCH data.

The URS may be transmitted in an RB in which resource mapping is performed on corresponding PDSCH data. Although R5 is indicated in FIG. 7 in addition to a region in which the PDSCH data is transmitted, this is for indicating a location of an RE to which the URS is mapped.

The URS may be a reference signal which is demodulated only by a specific UE. An RS (reference signal) sequence r_(l,n) _(s) (m) for the URS is equivalent to Equation 3. In this case, m=0, 1, . . . , 12N_(RB) ^(PDSCH)−1, and N_(RB) ^(PDSCH) is the number of RBs used for transmission of a corresponding PDSCH. If the URS is transmitted through a single antenna, a pseudo-random sequence generator is initialized as c_(init)=(└n_(s)/2┘+1)·(2N_(ID) ^(cell)+1)·2¹⁶+n_(RNTI) at a start of each subframe. n_(RNTI) is an identifier of a wireless device.

The aforementioned initialization method is for a case where the URS is transmitted through the single antenna, and when the URS is transmitted through multiple antennas, the pseudo-random sequence generator is initialized as c_(init)=(└n_(s)/2┘+1)·(2n_(ID) ^((n) ^(SCID) ⁾+1)·2^(16n)+n_(SCID) at a start of each subframe. n_(SCID) is a parameter acquired from a DL (downlink) grant (e.g., a DCI format 2B or 2C) related to PDSCH transmission.

The URS supports MIMO (Multiple Input Multiple Output) transmission. According to an antenna port or a layer, an RS sequence for the URS may be spread into a spread sequence as follows.

TABLE 7 Layer [ w(0) w(1) w(2) w(3) ] 1 [ +1 +1 +1 +1 ] 2 [ +1 −1 +1 −1 ] 3 [ +1 +1 +1 +1 ] 4 [ +1 −1 +1 −1 ] 5 [ +1 +1 −1 −1 ] 6 [ −1 −1 +1 +1 ] 7 [ +1 −1 −1 +1 ] 8 [ −1 +1 +1 −1 ]

A layer may be defined as an information path which is input to a precoder. A rank is a non-zero eigenvalue of a MIMO channel matrix, and is equal to the number of layers or the number of spatial streams. The layer may correspond to an antenna port for identifying a URS and/or a spread sequence applied to the URS.

Meanwhile, the PDCCH is monitored in an area restricted to the control region in the subframe, and a CRS transmitted in a full band is used to demodulate the PDCCH. As a type of control data is diversified and an amount of control data is increased, scheduling flexibility is decreased when using only the existing PDCCH. In addition, in order to decrease an overhead caused by CRS transmission, an EPDCCH (enhanced PDCCH) is introduced.

FIG. 8 is an example of a subframe having an EPDCCH.

The subframe may include zero or one PDCCH region 810 and zero or more EPDCCH regions 820 and 830.

The EPDCCH regions 820 and 830 are regions in which a UE monitors the EPDCCH. The PDCCH region 810 is located in first three or up to 4 OFDM symbols of the subframe, whereas the EPDCCH regions 820 and 830 may be flexibly scheduled in an OFDM symbol located after the PDCCH region 810.

One or more EPDCCH regions 820 and 830 may be assigned to the UE. The UE may monitor EPDDCH data in the assigned EPDCCH regions 820 and 830.

The number/location/size of the EPDCCH regions 820 and 830 and/or information regarding a subframe for monitoring the EPDCCH may be reported by a BS to the UE by using an RRC (radio resource control) message or the like.

In the PDCCH region 810, a PDCCH may be demodulated on the basis of a CRS. In the EPDCCH regions 820 and 830, instead of the CRS, a DM-RS may be defined for demodulation of the EPDCCH. The DM-RS may be transmitted in corresponding EPDCCH regions 820 and 830.

An RS sequence for the DM-RS is equivalent to Equation 3. In this case, m=0, 1, . . . , 12N_(RB) ^(max,DL)−1, and N_(RB) ^(max,DL), and N_(RB) ^(max,DL) is a maximum number of RBs. A pseudo-random sequence generator may be initialized as c_(init)=(└n_(s)/2┘+1)·(2n_(ID,i) ^(EPDCCH)+1)·(2¹⁶+n_(SCID) ^(EPDCCH) at a start of each subframe. ns is a slot number of a radio frame. n_(ID,i) ^(EPDCCH) is a cell index related to a corresponding EPDCCH region. n_(SCID) ^(EPDCCH) is a parameter given from higher layer signaling.

Each of the EPDCCH regions 820 and 830 may be used to schedule a different cell. For example, an EPDCCH in the EPDCCH region 820 may carry scheduling information for a primary cell, and an EPDCCH in the EPDCCH region 830 may carry scheduling information for a secondary cell.

When the EPDCCH is transmitted through multiple antennas in the EPDCCH regions 820 and 830, the same precoding as that used in the EPDCCH may be applied to a DM-RS in the EPDCCH regions 820 and 830.

Comparing with a case where the PDCCH uses a CCE as a transmission resource unit, a transmission resource unit for the EPDCCH is called an ECCE (Enhanced Control Channel Element). An aggregation level may be defined as a resource unit for monitoring the EPDCCH. For example, when 1 ECCE is a minimum resource for the EPDCCH, it may be defined as an aggregation level L={1, 2, 4, 8, 16}. A search space may also be defined in an EPDCCH region. The UE may monitor an EPDCCH candidate on the basis of the aggregation level.

FIG. 9 shows the concept of a method of processing a downlink transport channel according to an embodiment of the present invention.

In FIG. 9, an operation of delivering a transport block to a physical layer via a transport channel is described.

An LTE physical layer uses a higher layer, i.e., a MAC layer and a transport channel, to provide an interface. In case of single-antenna transmission, one transport block having a dynamic size exists for each TTI (transmission time interval). For example, in case of multi-antenna transmission, a transport block having a dynamic size may exist in plural (e.g., up to two) for each TTI.

In FIG. 9, a processing procedure for DL-SCH transmission is described when performing an LTE downlink transmission process. A second processing procedure corresponding to a second transport block exists only in case of downlink spatial multiplexing. In the case of downlink spatial multiplexing, two transport blocks each having a different size may be combined through antenna mapping in general. Hereinafter, an LTE downlink transport channel processing method of FIG. 14 is described.

(1) Inserting CRC Per Transport Block

In a first step of transport channel processing, a 24-bit CRC may be calculated and attached to each transport block. By using the CRC, an error may be detected in a decoded transport block in a receiving end. When the detected error is reported and thus retransmission is requested, for example, a downlink HARQ protocol may be used.

(2) Segmenting Code Block and Inserting CRC Per Transport Block

An internal interleaver of an LTE turbo code may be restricted in a size thereof, and thus may be defined only for a code block size of which a maximum block size is limited to a specific bit. If a size of a transport block including a CRC attached to the transport block exceeds a maximum code block size, code block segmentation may be performed before turbo coding. The segmentation of the code block implies that the transport block is divided into smaller sized code blocks to conform to code block sizes defined in a turbo code.

FIG. 10 shows the concept of a method of performing code block segmentation.

Referring to FIG. 10, code block segmentation may imply that an additional CRC is calculated and attached for each code block. A code block which is correctly coded can be known more rapidly when each code block has a CRC. Accordingly, iterative decoding on a corresponding code block can be finished more rapidly. Therefore, processing power consumption of a UE can be decreased. If one transport block is one code block in the absence of the code block segmentation, the CRC may not be added to the code block.

In the presence of the code block segmentation, whether the entirety of the transport block is correctly received can also be known indirectly from each of code block CRCs. In addition, by performing additional error detection based on the transport block CRC, it is possible to decrease a risk in which an error is not detected from a decoded transport block.

(3) Turbo Coding

In LTE, the existing WCDMA/HSPA turbo encoder internal interleaver is replaced with QPP (quadrature permutation polynomial)-based interleaving. Unlike the interleaver of the WCDMA/HSPA turbo code, the QPP-based interleaver is a maximum contention-free interleaver, and thus parallelization of a decoding process is possible simply without a collision risk even if different parallel processes access to an interleaver memory.

(4) Rate Matching and Physical Layer HARQ Function

Rate matching and physical layer HARQ take a role of correctly determining bits to be transmitted within a given TTI from blocks of code bits delivered from a channel encoder. Outputs of the turbo encoder (i.e., systematic bits, first parity bits, and second parity bits) may be preferentially interleaved respectively. The interleaved bits may enter to a circular buffer. A bit selection block extracts consecutive bits from the circular buffer by an amount of allocated resources.

FIG. 11 shows the concept of a method of performing rate matching.

Referring to FIG. 11, since a constant amount of radio resources are used in actual transmission, to cope with this situation, rate matching must be performed on an encoded code block. In general, the rate matching is achieved through puncturing or repetition. The rate matching may be performed in unit of an encoded code block such as WCDMA of 3GPP. It is shown in FIG. 11 that the method is performed separately on a system bit part and a parity bit part of the encoded code block. It is assumed herein that a code rate is ⅓.

(5) Bit-Based Scrambling

LTE downlink scrambling implies that a block of code bits subjected to rate matching and HARQ is multiplied by a bit-based scrambling sequence. In LTE, downlink scrambling may be applied to a coded bit of each transport channel.

(6) Data Modulation

Downlink data modulation indicates a process of converting scrambled bits into complex-valued modulation symbols. Examples of a modulation scheme supported in an LTE downlink include QPSK, 16QAM, and 64QAM. Hereinafter, a case where 256 QAM is additionally supported as the modulation scheme will be described in the exemplary embodiment of the present invention. The modulation scheme may use 2 bits, 4 bits, and 6 bits respectively for QPSK, 16QAM, and 64QAM. Different modulation schemes may be used according to a transport channel.

(7) Antenna Mapping

In general, antenna mapping takes a role of simultaneously processing modulation symbols corresponding to two transport blocks and of mapping results thereof to different antenna ports.

(8) Resource Block Mapping

Resource block mapping takes a role of mapping symbols to be transmitted to respective antenna ports to a resource element of resource blocks allocated to transport blocks transmitted to a UE by using a MAC scheduler.

Some resource elements in the resource block are preoccupied by different antenna ports or control regions, and such resource elements cannot be used.

A BS may use a downlink control channel (e.g., PDCCH, EPDCCH) to deliver a data block size to a UE. Information on the data block size transmitted through a PDSCH may be transmitted based on resource allocation information and MCS which is modulation and coding rate related information. For an MCS field, MCS information may be transmitted to the UE on the basis of 5 bits for example. For resource allocation, one RB to 110 RBs may be allocated. If all of the 5 bits of the MCS field are used to transmit the MCS information without having to use MIMO, 32 pieces of MCS information may be transmitted based on the 5 bits. In this case, signaling is possible for a data block size corresponding to 32×110. However, since 3 pieces of MCS information out of the 32 pieces of MCS information are used to indicate a change of a modulation scheme when performing retransmission, signaling is actually possible for a data block size corresponding to 29×110. The data block may imply a transport block.

QPSK, 16QAM, and 64QAM may be used as a modulation scheme supported in the existing LTE system. At a switching point at which the modulation scheme is changed, the same data block size may be indicated when the same resource is allocated. This is to effectively perform an operation in various channel environments. In order to indicate an actual data block size, IMCS which is MCS related information transmitted through a downlink control channel may be mapped to ITBS which is another variable for indicating a data block size. Table 8 below shows a relation between IMCS and ITBS.

TABLE 8 Modulation MCS Index Order TBS Index I_(MCS) Q_(m) I_(TBS) 0 2 0 1 2 1 2 2 2 3 2 3 4 2 4 5 2 5 6 2 6 7 2 7 8 2 8 9 2 9 10 4 9 11 4 10 12 4 11 13 4 12 14 4 13 15 4 14 16 4 15 17 6 15 18 6 16 19 6 17 20 6 18 21 6 19 22 6 20 23 6 21 24 6 22 25 6 23 26 6 24 27 6 25 28 6 26 29 2 reserved 30 4 31 6

The transport block size transmitted in a downlink may be determined by combining a resource allocation and an MCS field transmitted through the downlink control channel. Table 9 and Table 10 below respectively show a transport block size in the aforementioned IMCS-to-ITBS relation of Table 8 respectively for resource allocation of 1 RB to 10 RBs and resource allocation of 101 RBs to 110 RBs.

TABLE 9 N_(PRB) I_(TBS) 1 2 3 4 5 6 7 8 9 10 0 16 32 56 88 120 152 176 208 224 256 1 24 56 88 144 176 208 224 256 328 344 2 32 72 144 176 208 256 296 328 376 424 3 40 104 176 208 256 328 392 440 504 568 4 56 120 208 256 328 408 488 552 632 696 5 72 144 224 328 424 504 600 680 776 872 6 328 176 256 392 504 600 712 808 936 1032 7 104 224 328 472 584 712 840 968 1096 1224 8 120 256 392 536 680 808 968 1096 1256 1384 9 136 296 456 616 776 936 1096 1256 1416 1544 10 144 328 504 680 872 1032 1224 1384 1544 1736 11 176 376 584 776 1000 1192 1384 1608 1800 2024 12 208 440 680 904 1128 1352 1608 1800 2024 2280 13 224 488 744 1000 1256 1544 1800 2024 2280 2536 14 256 552 840 1128 1416 1736 1992 2280 2600 2856 15 280 600 904 1224 1544 1800 2152 2472 2728 3112 16 328 632 968 1288 1608 1928 2280 2600 2984 3240 17 336 696 1064 1416 1800 2152 2536 2856 3240 3624 18 376 776 1160 1544 1992 2344 2792 3112 3624 4008 19 408 840 1288 1736 2152 2600 2984 3496 3880 4264 20 440 904 1384 1864 2344 2792 3240 3752 4136 4584 21 488 1000 1480 1992 2472 2984 3496 4008 4584 4968 22 520 1064 1608 2152 2664 3240 3752 4264 4776 5352 23 552 1128 1736 2280 2856 3496 4008 4584 5160 5736 24 584 1192 1800 2408 2984 3624 4264 4968 5544 5992 25 616 1256 1864 2536 3112 3752 4392 5160 5736 6200 26 712 1480 2216 2984 3752 4392 5160 5992 6712 7480

TABLE 10 N_(PRB) I_(TBS) 101 102 103 104 105 106 107 108 109 110 0 2792 2856 2856 2856 2984 2984 2984 2984 2984 3112 1 3752 3752 3752 3752 3880 3880 3880 4008 4008 4008 2 4584 4584 4584 4584 4776 4776 4776 4776 4968 4968 3 5992 5992 5992 5992 6200 6200 6200 6200 6456 6456 4 7224 7224 7480 7480 7480 7480 7736 7736 7736 7992 5 8760 9144 9144 9144 9144 9528 9528 9528 9528 9528 6 10680 10680 10680 10680 11064 11064 11064 11448 11448 11448 7 12216 12576 12576 12576 12960 12960 12960 12960 13536 13536 8 14112 14112 14688 14688 14688 14688 15264 15264 15264 15264 9 15840 16416 16416 16416 16416 16992 16992 16992 16992 17568 10 17568 18336 18336 18336 18336 18336 19080 19080 19080 19080 11 20616 20616 20616 21384 21384 21384 21384 22152 22152 22152 12 22920 23688 23688 23688 23688 24496 24496 24496 24496 25456 13 26416 26416 26416 26416 27376 27376 27376 27376 28336 28336 14 29296 29296 29296 29296 30576 30576 30576 30576 31704 31704 15 30576 31704 31704 31704 31704 32856 32856 32856 34008 34008 16 32856 32856 34008 34008 34008 34008 35160 35160 35160 35160 17 36696 36696 36696 37888 37888 37888 39232 39232 39232 39232 18 40576 40576 40576 40576 42368 42368 42368 42368 43816 43816 19 43816 43816 43816 45352 45352 45352 46888 46888 46888 46888 20 46888 46888 48936 48936 48936 48936 48936 51024 51024 51024 21 51024 51024 51024 52752 52752 52752 52752 55056 55056 55056 22 55056 55056 55056 57336 57336 57336 57336 59256 59256 59256 23 57336 59256 59256 59256 59256 61664 61664 61664 61664 63776 24 61664 61664 63776 63776 63776 63776 66592 66592 66592 66592 25 63776 63776 66592 66592 66592 66592 68808 68808 68808 71112 26 75376 75376 75376 75376 75376 75376 75376 75376 75376 75376

In the embodiment of the present invention, a method of determining a size of transport block (or data block) is described when 256QAM is supported as a modulation scheme other than QPSK, 16QAM, and 64QAM supported in the existing LTE system.

The size of transport block may be determined by distinguishing a case where the transport block is subjected to channel coding as a single code block without being segmented in a process of code block segmentation and per-code block CRC insertion and a case where the transport block is subjected to channel coding by being segmented into multiple code blocks. If the transport block size including a CRC attached to the transport block exceeds a maximum code block size, the code block segmentation may be performed before turbo coding. The segmentation of code block implies that the transport block is segmented into smaller-sized code blocks to conform to a code block size defined in the turbo code.

In a case where channel coding is performed with the single code block without being segmented in the process of code block segmentation and per-code block CRC insertion, the transport block size may be determined according to an internal interleaver size of a turbo code in order not to attach a dummy bit to the code block.

Table 11 below shows the size of the turbo code internal interleaver.

TABLE 11 i L 1 40 2 48 3 56 4 64 5 72 6 80 7 88 8 96 9 104 10 112 11 120 12 128 13 136 14 144 15 152 16 160 17 168 18 176 19 184 20 192 21 200 22 208 23 216 24 224 25 232 26 240 27 248 28 256 29 264 30 272 31 280 32 288 33 296 34 304 35 312 36 320 37 328 38 336 39 344 40 352 41 360 42 368 43 376 44 384 45 392 46 400 47 408 48 416 49 424 50 432 51 440 52 448 53 456 54 464 55 472 56 480 57 488 58 496 59 504 60 512 61 528 62 544 63 560 64 576 65 592 66 608 67 624 68 640 69 656 70 672 71 688 72 704 73 720 74 736 75 752 76 768 77 784 78 800 79 816 80 832 81 848 82 864 83 880 84 896 85 912 86 928 87 944 88 960 89 976 90 992 91 1008 92 1024 93 1056 94 1088 95 1120 96 1152 97 1184 98 1216 99 1248 100 1280 101 1312 102 1344 103 1376 104 1408 105 1440 106 1472 107 1504 108 1536 109 1568 110 1600 111 1632 112 1664 113 1696 114 1728 115 1760 116 1792 117 1824 118 1856 119 1888 120 1920 121 1952 122 1984 123 2016 124 2048 125 2112 126 2176 127 2240 128 2304 129 2368 130 2432 131 2496 132 2560 133 2624 134 2688 135 2752 136 2816 137 2880 138 2944 139 3008 140 3072 141 3136 142 3200 143 3264 144 3328 145 3392 146 3456 147 3520 148 3584 149 3648 150 3712 151 3776 152 3840 153 3904 154 3968 155 4032 156 4096 157 4160 158 4224 159 4288 160 4352 161 4416 162 4480 163 4544 164 4608 165 4672 166 4736 167 4800 168 4864 169 4928 170 4992 171 5056 172 5120 173 5184 174 5248 175 5312 176 5376 177 5440 178 5504 179 5568 180 5632 181 5696 182 5760 183 5824 184 5888 185 5952 186 6016 187 6080 188 6144

In Table 11, i may denote an index of a turbo code internal interleaver, and L may denote a size of the turbo code internal interleaver. According to the embodiment of the present invention, the transport block size may be defined according to the size of the turbo code internal interleaver. That is, the dummy bit may be removed by limiting the transport block size to L.

Bits input to the turbo code internal interleaver may be denoted by c₀, c₁, . . . , c_(L-1). Herein, L denotes the number of input bits as a transport block size. Output bits calculated via the turbo code internal interleaver may be denoted by c′₀, c′₁, . . . , c′_(L-1). The input bit and the output bit may satisfy the relation of Equation 5 below. c′ _(i) =c _(Π(i)) ,i=0,1, . . . ,(L−1)  <Equation 5>

Herein, an output index i and an input index Π(i) may satisfy Equation 6 below. Π(i)=(f ₁ ·i+f ₂ ·i ²)mod L  <Equation 6>

In Equation 6, a parameter f₁ and a parameter f₂ may be values determined by a table on the basis of a size L of a turbo code internal interleaver (or a size of a transport block).

According to the embodiment of the present invention, the dummy bit may be removed in channel coding if the transport block size is defined to be equal to the turbo code internal interleaver size L defined in Table 11. It is assumed herein that the size of the transport block input to the turbo code internal interleaver is a size considering CRC attachment. For example, if a 24-bit CRC is attached, the transport block size is L−24 which is obtained by subtracting 24 bits from the block size defined in Table 11. That is, in the embodiment of the present invention, the dummy bit may be removed by defining the transport block size to N=L−A. Herein, N, L, and A may respectively denote the transport block size, the turbo code internal interleaver size, and the CRC-bit size.

If channel coding is performed by segmenting the transport block into multiple code blocks, the transport block size may be determined as follows. If the transport block is segmented into two or more code blocks, a CRC is attached to the transport block, and the CRC may also be attached to each segmented code block. When performing turbo coding on the transport block, a size corresponding to a sum of the code block size and a size of CRC attached to the code block must be set to the same as the internal interleaver size defined in Table 11 described above. In addition, it may be determined such that an error rate is not different between code blocks by equally setting the size of the segmented code block.

Then, if it is assumed that a transport block with a size N is segmented into M (M>=2) code blocks each having a size L (where L is a size of a turbo code internal interleaver) and a CRC size is A (e.g., 24 bits), Equation 7 below must be satisfied so that the code blocks have the same size. N+A×M+24=M*(L+A) N=M×L−A  <Equation 7>

The transport block size may be calculated by using Equation 7. The values L and M may be calculated by considering the defined turbo code internal interleaver size, and may be determined such that a dummy bit is not generated when performing turbo coding on each code block.

Table 12 below shows a case where there are up to 24 code blocks among transport blocks satisfying the aforementioned condition. It is assumed in Table 12 that a CRC size is 24, and if the CRC size is changed, another value may be determined to the transport block size.

TABLE 12 M N 2 6200 2 6328 2 6456 2 6584 2 6712 2 6840 2 6968 2 7096 2 7224 2 7352 2 7480 2 7608 2 7736 2 7864 2 7992 2 8120 2 8248 2 8376 2 8504 2 8632 2 8760 2 8888 2 9016 2 9144 2 9272 2 9400 2 9528 2 9656 2 9784 2 9912 2 10040 2 10168 2 10296 2 10424 2 10552 2 10680 2 10808 2 10936 2 11064 2 11192 2 11320 2 11448 2 11576 2 11704 2 11832 2 11960 2 12088 2 12216 3 12384 3 12576 3 12768 3 12960 3 13152 3 13344 3 13536 3 13728 3 13920 3 14112 3 14304 3 14496 3 14688 3 14880 3 15072 3 15264 3 15456 3 15648 3 15840 3 16032 3 16224 3 16416 3 16608 3 16800 3 16992 3 17184 3 17376 3 17568 3 17760 3 17952 3 18144 3 18336 3 12384 4 18568 4 18824 4 19080 4 19336 4 19592 4 19848 4 20104 4 20360 4 20616 4 20872 4 21128 4 21384 4 21640 4 21896 4 22152 4 22408 4 22664 4 22920 4 23176 4 23432 4 23688 4 23944 4 24200 4 24456 5 24496 5 24816 5 25136 5 25456 5 25776 5 26096 5 26416 5 26736 5 27056 5 27376 5 27696 5 28016 5 28336 5 28656 5 28976 5 29296 5 29616 5 29936 5 30256 5 30576 6 30936 5 31320 5 31704 6 32088 6 32472 6 32856 6 33240 6 33624 6 34008 6 34392 6 34776 6 35160 6 35544 6 35928 6 36312 6 36696 6 30936 6 31320 7 36992 7 37440 7 37888 7 38336 7 38784 7 39232 7 39680 7 40128 7 40576 7 41024 7 41472 7 41920 7 42368 7 42816 7 36992 8 42792 8 43304 8 43816 8 44328 8 44840 8 45352 8 45864 8 46376 8 46888 8 47400 8 47912 8 48424 8 49320 9 49296 9 49872 9 50448 9 51024 9 51600 9 52176 9 52752 9 53328 9 53904 9 54480 9 55488 10 55416 10 56056 10 56696 10 57336 10 57976 10 58616 10 59256 10 59896 10 60536 10 61656 11 61664 11 62368 11 63072 11 63776 11 64480 11 65184 11 65888 11 66592 11 67824 12 68040 12 68808 12 69576 12 70344 12 71112 12 71880 12 72648 12 73992 13 74544 13 75376 13 76208 13 77040 13 77872 13 78704 13 80160 14 80280 14 81176 14 82072 14 82968 14 83864 14 84760 14 85656 14 80280 14 81176 15 86016 15 86976 15 87936 15 88896 15 89856 15 90816 15 91776 16 92776 16 93800 16 94824 16 95848 16 96872 16 97896 17 98576 17 99664 17 100752 17 101840 17 102928 17 104016 18 104376 18 105528 18 106680 18 107832 18 108984 18 110136 19 111392 19 112608 19 113824 19 115040 19 116256 20 117256 20 118536 20 119816 20 121096 20 123336 21 124464 21 125808 21 127152 21 129504 22 130392 22 131800 22 133208 22 134616 23 136320 23 137792 23 139264 23 140736 24 142248 24 143784 24 145320 24 146856

In Table 12, M denotes the number of code blocks segmented from one transport block, and N denotes a size of transport block. The size of transport block may be set differently according to the number of segmented code blocks.

When using the size of transport block defined in Table 11 and Table 12, a dummy bit may not be generated when performing channel coding. Accordingly, the same performance may be guaranteed between code blocks. Therefore, according to the embodiment of the present invention, the size of transport block may be calculated and used on the basis of Equation 6 and Equation 7 depending on the number of code blocks segmented from one transport block.

For example, on the basis of a combination of a modulation and coding rate and an allocation resource size, a BS may report to a UE about information on a size of transport block transmitted by the BS. The size of transport block may be expressed with the combination of the modulation and coding rate and the allocated resource size. The BS may determine the modulation and coding rate to be applied to a coded block by referring to a channel quality indicator transmitted by the UE. A size of resource allocated to the coded block may also be determined by considering a resource for transmitting control information and a resource for a reference signal for channel estimation.

FIG. 12 shows the concept of a resource block pair according to an embodiment of the present invention.

Referring to FIG. 12, a horizontal axis represents a time domain, and a vertical axis represents a frequency domain.

In the resource block pair of FIG. 12, it may be assumed that resources for control information transmission are first three OFDM symbols (i.e., an OFDM symbol 0, an OFDM symbol 1, and an OFDM symbol 2) and reference signals are transmitted through two transmit antennas. In this case, the number of REs (resource elements) that can be used for data transmission may be 120 in one unit RBP (resource block pair).

For example, it may be assumed that a modulation scheme and a coding rate used by a BS are 64QAM and 0.6504 and the number of allocated RBs is 10. A size of transport block that can be transmitted through allocated 10 RBs is 4658 bits. This is a value in the range between 4608 bits and 4672 bits, i.e., the transport block size defined in Table 11 above. By defining a rule for determining the size of transport block to any one of the defined two transport block sizes, the size of transport block may be determined according to various modulation and code rates and allocated resource sizes.

In a case where a size of transport block that can be actually transmitted is not equal to a supportable transport block size as described above, the size of transport block may be determined according to a specific rule. For example, according to the embodiment of the present invention, if the size of transport block is not equal to the supportable transport block size, the size of transport block that can be actually transmitted may be determined by using any one of the following rules.

i) Method of determining a transport block size to a maximum supportable transport block size not exceeding an actually transmissible transport block size.

ii) Method of determining a transport block size to a minimum supportable transport block size exceeding an actually transmissible transport block size.

iii) Method of determining a transport block size to a supportable data block having a smallest difference with respect to an actually transmissible data block size.

Table 13 below shows an example of a case where the number of code blocks is in the range of 25 to 66 among transport blocks satisfying the aforementioned condition. It is shown in Table 13 that a size of transport block is defined variously according to a modulation scheme, a coding rate, and an allocated resource even if the same number of code blocks are present. A transport block defined in a case of using 256QAM as the modulation scheme is also included in Table 13. In Table 13, an uppermost end may indicate the number of code blocks, and a value included in a column mapped according to the number of code blocks may be a size of transport block defined variously according to a modulation and coding rate. According to the embodiment of the present invention, one of the sizes of transport blocks defined in the following table may be used when determining the size of transport block.

TABLE 13 25 26 27 28 29 30 31 32 33 76176 79224 82272 85320 88368 91416 94464 97512 100560 77776 80888 84000 87112 90224 93336 96448 99560 102672 79376 82552 85728 88904 92080 95256 98432 101608 104784 80976 84216 87456 90696 93936 97176 100416 103656 106896 82576 85880 89184 92488 95792 99096 102400 105704 109008 84176 87544 90912 94280 97648 101016 104384 107752 111120 85776 89208 92640 96072 99504 102936 106368 109800 113232 87376 90872 94368 97864 101360 104856 108352 111848 115344 88976 92536 96096 99656 103216 106776 110336 113896 117456 90576 94200 97824 101448 105072 108696 112320 115944 119568 92176 95864 99552 103240 106928 110616 114304 117992 121680 93776 97528 101280 105032 108784 112536 116288 120040 123792 95376 99192 103008 106824 110640 114456 118272 122088 125904 96976 100856 104736 108616 112496 116376 120256 124136 128016 98576 102520 106464 110408 114352 118296 122240 126184 130128 100176 104184 108192 112200 116208 120216 124224 128232 132240 101776 105848 109920 113992 118064 122136 126208 130280 134352 103376 107512 111648 115784 119920 124056 128192 132328 136464 104976 109176 113376 117576 121776 125976 130176 134376 138576 106576 110840 115104 119368 123632 127896 132160 136424 140688 108176 112504 116832 121160 125488 129816 134144 138472 142800 109776 114168 118560 122952 127344 131736 136128 140520 144912 111376 115832 120288 124744 129200 133656 138112 142568 147024 112976 117496 122016 126536 131056 135576 140096 144616 149136 114576 119160 123744 128328 132912 137496 142080 146664 151248 116176 120824 125472 130120 134768 139416 144064 148712 153360 117776 122488 127200 131912 136624 141336 146048 150760 155472 119376 124152 128928 133704 138480 143256 148032 152808 157584 120976 125816 130656 135496 140336 145176 150016 154856 159696 122576 127480 132384 137288 142192 147096 152000 156904 161808 124176 129144 134112 139080 144048 149016 153984 158952 163920 125776 130808 135840 140872 145904 150936 155968 161000 166032 127376 132472 137568 142664 147760 152856 157952 163048 168144 128976 134136 139296 144456 149616 154776 159936 165096 170256 130576 135800 141024 146248 151472 156696 161920 167144 172368 132176 137464 142752 148040 153328 158616 163904 169192 174480 133776 139128 144480 149832 155184 160536 165888 171240 176592 135376 140792 146208 151624 157040 162456 167872 173288 178704 136976 142456 147936 153416 158896 164376 169856 175336 180816 138576 144120 149664 155208 160752 166296 171840 177384 182928 140176 145784 151392 157000 162608 168216 173824 179432 185040 141776 147448 153120 158792 164464 170136 175808 181480 187152 143376 149112 154848 160584 166320 172056 177792 183528 189264 144976 150776 156576 162376 168176 173976 179776 185576 191376 146576 152440 158304 164168 170032 175896 181760 187624 193488 148176 154104 160032 165960 171888 177816 183744 189672 195600 149776 155768 161760 167752 173744 179736 185728 191720 197712 151376 157432 163488 169544 175600 181656 187712 193768 199824 152976 159096 165216 171336 177456 183576 189696 195816 201936 34 35 36 37 38 39 40 41 42 103608 106656 109704 112752 115800 118848 121896 124944 127992 105784 108896 112008 115120 118232 121344 124456 127568 130680 107960 111136 114312 117488 120664 123840 127016 130192 133368 110136 113376 116616 119856 123096 126336 129576 132816 136056 112312 115616 118920 122224 125528 128832 132136 135440 138744 114488 117856 121224 124592 127960 131328 134696 138064 141432 116664 120096 123528 126960 130392 133824 137256 140688 144120 118840 122336 125832 129328 132824 136320 139816 143312 146808 121016 124576 128136 131696 135256 138816 142376 145936 149496 123192 126816 130440 134064 137688 141312 144936 148560 152184 125368 129056 132744 136432 140120 143808 147496 151184 154872 127544 131296 135048 138800 142552 146304 150056 153808 157560 129720 133536 137352 141168 144984 148800 152616 156432 160248 131896 135776 139656 143536 147416 151296 155176 159056 162936 134072 138016 141960 145904 149848 153792 157736 161680 165624 136248 140256 144264 148272 152280 156288 160296 164304 168312 138424 142496 146568 150640 154712 158784 162856 166928 171000 140600 144736 148872 153008 157144 161280 165416 169552 173688 142776 146976 151176 155376 159576 163776 167976 172176 176376 144952 149216 153480 157744 162008 166272 170536 174800 179064 147128 151456 155784 160112 164440 168768 173096 177424 181752 149304 153696 158088 162480 166872 171264 175656 180048 184440 151480 155936 160392 164848 169304 173760 178216 182672 187128 153656 158176 162696 167216 171736 176256 180776 185296 189816 155832 160416 165000 169584 174168 178752 183336 187920 192504 158008 162656 167304 171952 176600 181248 185896 190544 195192 160184 164896 169608 174320 179032 183744 188456 193168 197880 162360 167136 171912 176688 181464 186240 191016 195792 200568 164536 169376 174216 179056 183896 188736 193576 198416 203256 166712 171616 176520 181424 186328 191232 196136 201040 205944 168888 173856 178824 183792 188760 193728 198696 203664 208632 171064 176096 181128 186160 191192 196224 201256 206288 211320 173240 178336 183432 188528 193624 198720 203816 208912 214008 175416 180576 185736 190896 196056 201216 206376 211536 216696 177592 182816 188040 193264 198488 203712 208936 214160 219384 179768 185056 190344 195632 200920 206208 211496 216784 222072 181944 187296 192648 198000 203352 208704 214056 219408 224760 184120 189536 194952 200368 205784 211200 216616 222032 227448 186296 191776 197256 202736 208216 213696 219176 224656 230136 188472 194016 199560 205104 210648 216192 221736 227280 232824 190648 196256 201864 207472 213080 218688 224296 229904 235512 192824 198496 204168 209840 215512 221184 226856 232528 238200 195000 200736 206472 212208 217944 223680 229416 235152 240888 197176 202976 208776 214576 220376 226176 231976 237776 243576 199352 205216 211080 216944 222808 228672 234536 240400 246264 201528 207456 213384 219312 225240 231168 237096 243024 248952 203704 209696 215688 221680 227672 233664 239656 245648 251640 205880 211936 217992 224048 230104 236160 242216 248272 254328 208056 214176 220296 226416 232536 238656 244776 250896 257016 43 44 45 46 47 48 49 50 51 131040 134088 137136 140184 143232 146280 149328 152376 155424 133792 136904 140016 143128 146240 149352 152464 155576 158688 136544 139720 142896 146072 149248 152424 155600 158776 161952 139296 142536 145776 149016 152256 155496 158736 161976 165216 142048 145352 148656 151960 155264 158568 161872 165176 168480 144800 148168 151536 154904 158272 161640 165008 168376 171744 147552 150984 154416 157848 161280 164712 168144 171576 175008 150304 153800 157296 160792 164288 167784 171280 174776 178272 153056 156616 160176 163736 167296 170856 174416 177976 181536 155808 159432 163056 166680 170304 173928 177552 181176 184800 158560 162248 165936 169624 173312 177000 180688 184376 188064 161312 165064 168816 172568 176320 180072 183824 187576 191328 164064 167880 171696 175512 179328 183144 186960 190776 194592 166816 170696 174576 178456 182336 186216 190096 193976 197856 169568 173512 177456 181400 185344 189288 193232 197176 201120 172320 176328 180336 184344 188352 192360 196368 200376 204384 175072 179144 183216 187288 191360 195432 199504 203576 207648 177824 181960 186096 190232 194368 198504 202640 206776 210912 180576 184776 188976 193176 197376 201576 205776 209976 214176 183328 187592 191856 196120 200384 204648 208912 213176 217440 186080 190408 194736 199064 203392 207720 212048 216376 220704 188832 193224 197616 202008 206400 210792 215184 219576 223968 191584 196040 200496 204952 209408 213864 218320 222776 227232 194336 198856 203376 207896 212416 216936 221456 225976 230496 197088 201672 206256 210840 215424 220008 224592 229176 233760 199840 204488 209136 213784 218432 223080 227728 232376 237024 202592 207304 212016 216728 221440 226152 230864 235576 240288 205344 210120 214896 219672 224448 229224 234000 238776 243552 208096 212936 217776 222616 227456 232296 237136 241976 246816 210848 215752 220656 225560 230464 235368 240272 245176 250080 213600 218568 223536 228504 233472 238440 243408 248376 253344 216352 221384 226416 231448 236480 241512 246544 251576 256608 219104 224200 229296 234392 239488 244584 249680 254776 259872 221856 227016 232176 237336 242496 247656 252816 257976 263136 224608 229832 235056 240280 245504 250728 255952 261176 266400 227360 232648 237936 243224 248512 253800 259088 264376 269664 230112 235464 240816 246168 251520 256872 262224 267576 272928 232864 238280 243696 249112 254528 259944 265360 270776 276192 235616 241096 246576 252056 257536 263016 268496 273976 279456 238368 243912 249456 255000 260544 266088 271632 277176 282720 241120 246728 252336 257944 263552 269160 274768 280376 285984 243872 249544 255216 260888 266560 272232 277904 283576 289248 246624 252360 258096 263832 269568 275304 281040 286776 292512 249376 255176 260976 266776 272576 278376 284176 289976 295776 252128 257992 263856 269720 275584 281448 287312 293176 299040 254880 260808 266736 272664 278592 284520 290448 296376 302304 257632 263624 269616 275608 281600 287592 293584 299576 305568 260384 266440 272496 278552 284608 290664 296720 302776 308832 263136 269256 275376 281496 287616 293736 299856 305976 312096 52 53 54 55 56 57 58 59 60 158472 161520 164568 167616 170664 173712 176760 179808 182856 161800 164912 168024 171136 174248 177360 180472 183584 186696 165128 168304 171480 174656 177832 181008 184184 187360 190536 168456 171696 174936 178176 181416 184656 187896 191136 194376 171784 175088 178392 181696 185000 188304 191608 194912 198216 175112 178480 181848 185216 188584 191952 195320 198688 202056 178440 181872 185304 188736 192168 195600 199032 202464 205896 181768 185264 188760 192256 195752 199248 202744 206240 209736 185096 188656 192216 195776 199336 202896 206456 210016 213576 188424 192048 195672 199296 202920 206544 210168 213792 217416 191752 195440 199128 202816 206504 210192 213880 217568 221256 195080 198832 202584 206336 210088 213840 217592 221344 225096 198408 202224 206040 209856 213672 217488 221304 225120 228936 201736 205616 209496 213376 217256 221136 225016 228896 232776 205064 209008 212952 216896 220840 224784 228728 232672 236616 208392 212400 216408 220416 224424 228432 232440 236448 240456 211720 215792 219864 223936 228008 232080 236152 240224 244296 215048 219184 223320 227456 231592 235728 239864 244000 248136 218376 222576 226776 230976 235176 239376 243576 247776 251976 221704 225968 230232 234496 238760 243024 247288 251552 255816 225032 229360 233688 238016 242344 246672 251000 255328 259656 228360 232752 237144 241536 245928 250320 254712 259104 263496 231688 236144 240600 245056 249512 253968 258424 262880 267336 235016 239536 244056 248576 253096 257616 262136 266656 271176 238344 242928 247512 252096 256680 261264 265848 270432 275016 241672 246320 250968 255616 260264 264912 269560 274208 278856 245000 249712 254424 259136 263848 268560 273272 277984 282696 248328 253104 257880 262656 267432 272208 276984 281760 286536 251656 256496 261336 266176 271016 275856 280696 285536 290376 254984 259888 264792 269696 274600 279504 284408 289312 294216 258312 263280 268248 273216 278184 283152 288120 293088 298056 261640 266672 271704 276736 281768 286800 291832 296864 301896 264968 270064 275160 280256 285352 290448 295544 300640 305736 268296 273456 278616 283776 288936 294096 299256 304416 309576 271624 276848 282072 287296 292520 297744 302968 308192 313416 274952 280240 285528 290816 296104 301392 306680 311968 317256 278280 283632 288984 294336 299688 305040 310392 315744 321096 281608 287024 292440 297856 303272 308688 314104 319520 324936 284936 290416 295896 301376 306856 312336 317816 323296 328776 288264 293808 299352 304896 310440 315984 321528 327072 332616 291592 297200 302808 308416 314024 319632 325240 330848 336456 294920 300592 306264 311936 317608 323280 328952 334624 340296 298248 303984 309720 315456 321192 326928 332664 338400 344136 301576 307376 313176 318976 324776 330576 336376 342176 347976 304904 310768 316632 322496 328360 334224 340088 345952 351816 308232 314160 320088 326016 331944 337872 343800 349728 355656 311560 317552 323544 329536 335528 341520 347512 353504 359496 314888 320944 327000 333056 339112 345168 351224 357280 363336 318216 324336 330456 336576 342696 348816 354936 361056 367176 61 62 63 64 65 66 185904 188952 192000 195048 198096 201144 189808 192920 196032 199144 202256 205368 193712 196888 200064 203240 206416 209592 197616 200856 204096 207336 210576 213816 201520 204824 208128 211432 214736 218040 205424 208792 212160 215528 218896 222264 209328 212760 216192 219624 223056 226488 213232 216728 220224 223720 227216 230712 217136 220696 224256 227816 231376 234936 221040 224664 228288 231912 235536 239160 224944 228632 232320 236008 239696 243384 228848 232600 236352 240104 243856 247608 232752 236568 240384 244200 248016 251832 236656 240536 244416 248296 252176 256056 240560 244504 248448 252392 256336 260280 244464 248472 252480 256488 260496 264504 248368 252440 256512 260584 264656 268728 252272 256408 260544 264680 268816 272952 256176 260376 264576 268776 272976 277176 260080 264344 268608 272872 277136 281400 263984 268312 272640 276968 281296 285624 267888 272280 276672 281064 285456 289848 271792 276248 280704 285160 289616 294072 275696 280216 284736 289256 293776 298296 279600 284184 288768 293352 297936 302520 283504 288152 292800 297448 302096 306744 287408 292120 296832 301544 306256 310968 291312 296088 300864 305640 310416 315192 295216 300056 304896 309736 314576 319416 299120 304024 308928 313832 318736 323640 303024 307992 312960 317928 322896 327864 306928 311960 316992 322024 327056 332088 310832 315928 321024 326120 331216 336312 314736 319896 325056 330216 335376 340536 318640 323864 329088 334312 339536 344760 322544 327832 333120 338408 343696 348984 326448 331800 337152 342504 347856 353208 330352 335768 341184 346600 352016 357432 334256 339736 345216 350696 356176 361656 338160 343704 349248 354792 360336 365880 342064 347672 353280 358888 364496 370104 345968 351640 357312 362984 368656 374328 349872 355608 361344 367080 372816 378552 353776 359576 365376 371176 376976 382776 357680 363544 369408 375272 381136 387000 361584 367512 373440 379368 385296 391224 365488 371480 377472 383464 389456 395448 369392 375448 381504 387560 393616 399672 373296 379416 385536 391656 397776 403896

All or some of the transport block sizes of Table 13 may be used as a transport block size in a system supporting 256QAM. In addition, some of the transport block sizes of Table 13 support 256QAM, and may be used as a size of transport block transmitted through 2-layer, 3-layer, 4-layer or 5-layer, 6-layer, 7-layer, 8-layer.

According to another embodiment of the present invention, a size of transport block may be determined by differently setting a rank supported depending on a modulation scheme. For example, some of the transport block sizes among the transport block sizes of Table 13 support 256QAM, and may be determined not to support a transport block size greater than or equal to 3-layer as a size of transport block transmitted with a specific rank or below (i.e., 2 layer or below).

FIG. 13 is a flowchart showing a method of performing turbo coding for a transport block according to an embodiment of the present invention.

Referring to FIG. 13, a size of transport block is determined (step S1300).

According to the embodiment of the present invention, an unnecessary dummy bit can be removed by determining the size of transport block according to a size of a turbo code internal interleaver.

The size of transport block may be determined according to whether one transport block is segmented into a single code block or multiple code blocks as described above. If the transport block is segmented into the single code block, the size of transport block may be a value obtained by subtracting a CRC bit size from the turbo code internal interleaver size. If the transport block is segmented into the multiple code blocks, the size of transport block may be a value obtained by subtracting a CRC bit size from a value obtained by multiplying a size of each code block by the number of segmented code blocks. The size of transport block may be determined by additionally considering a modulation scheme (e.g., 64QAM, 256QAM) and an allocation resource.

For turbo coding, the transport block is subjected to code block segmentation (step S1320).

In the code block segmentation, a single transport block may be determined to the code block when the single transport block is not segmented into multiple code blocks. If the single transport block is segmented into the multiple code blocks, the single transport block may be determined to the multiple code blocks.

On the basis of the turbo code internal interleaver, data included in the code block is interleaved (step S1340).

The turbo code internal interleaver may interleave the data included in the code block. A size of interleaved code block may be a value obtained by considering the turbo code internal interleaver size as described above.

Turbo coding is performed on the interleaved code block (step S1360).

The turbo coding may be performed on the interleaved code block. A size of code block may be determined by considering the turbo code internal interleaver size, thereby being able to reduce a dummy bit generated in turbo coding.

FIG. 14 is a block diagram of a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 14, a BS 1400 includes a processor 1410, a memory 1420, and a radio frequency (RF) unit 1430. The memory 1420 is coupled to the processor 1410, and stores a variety of information for driving the processor 1410. The RF unit 1420 is coupled to the processor 1410, and transmits and/or receives a radio signal. The processor 1410 implements the proposed functions, procedures, and/or methods. In the aforementioned embodiment, an operation of the BS may be implemented by the processor 1410.

For example, the processor 1410 determines a size of a transport block, divides the transport block into at least one code block based on the size of transport block, interleaves the at least one code block by an interleaver, and performs a turbo coding for the interleaved at least one code block. The processor 1410 may be determined based on the number of the divided code blocks.

A wireless device 1450 includes a processor 1460, a memory 1470, and an RF unit 1480. The memory 1470 is coupled to the processor 1460, and stores a variety of information for driving the processor 1460. The RF unit 1480 is coupled to the processor 1460, and transmits and/or receives a radio signal. The processor 1460 implements the proposed functions, procedures, and/or methods. In the aforementioned embodiment, an operation of the wireless device may be implemented by the processor 1460.

For example, the processor 1460 determines a size of a transport block, divides the transport block into at least one code block based on the size of transport block, interleaves the at least one code block by an interleaver, and performs a turbo coding for the interleaved at least one code block. The processor 1460 may be determined based on the number of the divided code blocks.

The processor may include an application-specific integrated circuit (ASIC), a separate chipset, a logic circuit, and a data processing unit. The memory may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium, and/or other equivalent storage devices. The RF unit may include a baseband circuit for processing a radio signal. When the embodiment of the present invention is implemented in software, the aforementioned methods can be implemented with a module (i.e., process, function, etc.) for performing the aforementioned functions. The module may be stored in the memory and may be performed by the processor. The memory may be located inside or outside the processor, and may be coupled to the processor by using various well-known means.

Although the aforementioned exemplary system has been described on the basis of a flowchart in which steps or blocks are listed in sequence, the steps of the present invention are not limited to a certain order. Therefore, a certain step may be performed in a different step or in a different order or concurrently with respect to that described above. Further, it will be understood by those ordinary skilled in the art that the steps of the flowcharts are not exclusive. Rather, another step may be included therein or one or more steps may be deleted within the scope of the present invention. 

What is claimed is:
 1. A method for encoding a transport block in a wireless communication system, the method comprising: determining, by a transmitter, a size of the transport block; attaching, by the transmitter, a first cyclic redundancy check (CRC) code to the transport block having the determined size to produce a first CRC-attached transport block; segmenting, by the transmitter, the first CRC-attached transport block into a plurality of code blocks when a size of the first CRC-attached transport block is larger than a maximum code block size; attaching, by the transmitter, a second CRC code to each of the plurality of code blocks to produce a plurality of second CRC-attached code blocks; and encoding, by the transmitter, the second CRC-attached code blocks by a turbo-encoder, wherein the size of the transport block is determined from among a plurality of first predetermined transport block sizes, wherein the size of the transport block is determined based on a 256 quadrature amplitude modulation (QAM) scheme, a size of an allocated resource, and a number of layers, wherein the plurality of the first predetermined transport block sizes includes 305976 bits, 324336 bits, and 391656 bits when the transport block is mapped to four-layer spatial multiplexing, and wherein the size of the transport block is determined from among a plurality of second predetermined transport block sizes to satisfy that a size of the first CRC-attached transport block is equal to an internal interleavers size of the turbo-encoder when the size of the first CRC-attached transport block is smaller than or equal to the maximum code block size.
 2. The method of claim 1, wherein a size of each of the code blocks is equal to a size corresponding to when the size of the transport block is the 305976 bits, the 324336 bits, or the 391656 bits, and an internal interleaver size of the turbo-encoder for encoding the second CRC-attached code blocks is
 6144. 3. The method of claim 1, wherein the plurality of predetermined first transport block sizes further includes 314888 bits, 339112 bits, 351224 bits, 363336 bits, and 375448 bits when the transport block is mapped to four-layer spatial multiplexing, and wherein a size of each of the code blocks is equal to a size corresponding to when the size of the transport block is the 314888 bits, the 339112 bits, the 351224 bits, the 363336 bits or the 375448 bits and an internal interleaver size of the turbo-encoder for encoding the second CRC-attached code blocks is
 6080. 4. The method of claim 1, wherein the turbo-encoder interleaves an input bit as follows, c′ _(i) =c _(Π(i)) ,i=0,1, . . . ,(L−1), where the c_(Π(i)) is an input bit of the internal interleaver, the c′_(i) is an output bit of the internal interleaver, the L is the size of the transport block, the i is an index of the input bit, where Π(i) is determined as below, Π(i)=(f ₁ ·i+f ₂ ·i ²)mod L, and wherein the f₁ and f₂ are predetermined values according to the L, the L is the size of the transport block, the i is the index of the input bit.
 5. The method of claim 1, wherein the size of the transport block is determined based on a value of a rank, the value of the rank being used by the transmitter, when the transmitter uses a multiple input multiple output (MIMO) spatial multiplexing to transmit the transport block, and wherein the value of the rank is restricted by the modulation scheme.
 6. A wireless apparatus configured for encoding a transport block in a wireless communication system, the wireless apparatus comprising: a transceiver configured to receive radio signals; and a processor configured to: determine a size of the transport block, attach a first cyclic redundancy check (CRC) code to the transport block having the determined size to produce a first CRC-attached transport block, segment the first CRC-attached transport block into a plurality of code blocks when a size of the first CRC-attached transport block is larger than a maximum code block size, attach a second CRC code to each of the plurality of code blocks to produce a plurality of second CRC-attached code blocks, and encode the second CRC-attached code blocks by a turbo-encoder, wherein the size of the transport block is determined from among a plurality of first predetermined transport block sizes, wherein the size of the transport block is determined based on a 256 quadrature amplitude modulation (QAM) scheme, a size of an allocated resource, and a number of layers, wherein the plurality of predetermined transport block sizes includes 305976 bits, 324336 bits, and 391656 bits when the transport block is mapped to four-layer spatial multiplexing, and wherein the size of the transport block is determined from among a plurality of second predetermined transport block sizes to satisfy that a size of the first CRC-attached transport block is equal to an internal interleavers size of the turbo-encoder when the size of the first CRC-attached transport block is smaller than or equal to the maximum code block size.
 7. The wireless apparatus of claim 6, wherein a size of each of the code blocks is equal to a size corresponding to when the size of the transport block is the 305976 bits, the 324336 bits, or the 391656 bits, and an internal interleaver size of the turbo-encoder for encoding the second CRC-attached code blocks is
 6144. 8. The wireless apparatus of claim 6, wherein the plurality of predetermined first transport block sizes further includes 314888 bits, 339112 bits, 351224 bits, 363336 bits, and 375448 bits when the transport block is mapped to four-layer spatial multiplexing, and wherein a size of each of the code blocks is equal to a size corresponding to when the size of the transport block is the 314888 bits, the 339112 bits, the 351224 bits, the 363336 bits or the 375448 bits and an internal interleaver size of the turbo-encoder for encoding the second CRC-attached code block is
 6080. 9. The wireless apparatus of claim 6, wherein the turbo-encoder interleaves an input bit as follows, c′ _(i) =c _(Π(i)) ,i=0,1, . . . ,(L−1), where the c_(Π(i)) is an input bit of the internal interleaver, c′_(i) the is an output bit of the internal interleaver, the L is the size of the transport block, the i is an index of the input bit, where Π(i) is determined as below, Π(i)=(f ₁ ·i+f ₂ ·i ²)mod L, and wherein the f₁ and f₂ are predetermined values according to the L, the L is the size of the transport block, the i is the index of the input bit.
 10. The wireless apparatus of claim 6, wherein the size of the transport block is determined based on a value of a rank, the value of the rank being used by the wireless apparatus, when the wireless apparatus uses a multiple input multiple output (MIMO) spatial multiplexing method to transmit the transport block, and wherein the value of the rank is restricted by the modulation scheme. 